The official name for the .NET Framework "Orcas" release will be called .NET Framework 3.5 (it includes the new LINQ support, integrated ASP.NET AJAX support, new ASP.NET data controls, and more).
Multi-TargetingPast few releases of Visual Studio, each Visual Studio release only supported a specific version of the .NET Framework. For example, VS 2002 only worked with .NET 1.0, VS 2003 only worked with .NET 1.1, and VS 2005 only worked with .NET 2.0.
One of the big changes starting with the VS 2008 release is to support "Multi-Targeting" - which means that Visual Studio will now support targeting multiple versions of the .NET Framework, and developers will be able to start taking advantage of the new features Visual Studio provides without having to always upgrade their existing projects and deployed applications to use a new version of the .NET Framework library.
Now when you open an existing project or create a new one with VS 2008, you can pick which version of the .NET Framework to work with - and the IDE will update its compilers and feature-set to match this. Among other things, this means that features, controls, projects, item-templates, and assembly references that don't work with that version of the framework will be hidden, and when you build your application you'll be able to take the compiled output and copy it onto a machine that only has an older version of the .NET Framework installed, and you'll know that the application will work.
Creating a new project in VS 2008 that targets .NET 2.0. While creating a project you can notice with dropdown with different .NET framework in it. You can select what type of Framework you want to use.After you select the framewrork, it will automatically filter the project list to only show those project templates supported on machines with the .NET 2.0 framework installed. If you create a new ASP.NET Web Application with the .NET 2.0 dropdown setting selected, it will create a new ASP.NET project whose compilation settings, assembly references, and web.config settings are configured to work with existing ASP.NET 2.0 servers.
why use VS 2008 if you aren't using the new .NET 3.5 features?Well, the good news is that you get a ton of tool-specific value with VS 2008 that you'll be able to take advantage of immediately with your existing projects without having to upgrade your framework/ASP.NET version. A few big tool features in the web development space I think you'll really like include:
- JavaScript intellisense
- Much richer JavaScript debugging
- Nested ASP.NET master page support at design-time
- Rich CSS editing and layout support within the WYSIWYG designer
- Split-view designer support for having both source and design views open on a page at the same time
- A much faster ASP.NET page designer - with dramatic perf improvements in view-switches between source/design mode
- Automated .SQL script generation and hosting deployment support for databases on remote servers
And also, you can upgrade or downgrade to any version on .NET framewrok by pulling properties and selecting the desired framework you want. This will automatically remove the newer assembly references from your project, update your web.config file, and allow you to compile against the older framework (note: if you have code in the project that was written against the new APIs, obviously you'll need to change it).
What about .NET 1.0 and 1.1?
Unfortunately the VS 2008 multi-targeting support only works with .NET 2.0, .NET 3.0 and .NET 3.5 - and not against older versions of the framework. The reason for this is that there were significant CLR engine changes between .NET 1.x and 2.x that make debugging very difficult to support. In the end the costing of the work to support that was so large and impacted so many parts of Visual Studio that we weren't able to add 1.1 support in this release.
VS 2008 does run side-by-side, though, with VS 2005, VS 2003, and VS 2002. So it is definitely possible to continue targeting .NET 1.1 projects using VS 2003 on the same machine as VS 2008.